HTML, CSS and JavaScript — What Each One Does

Every web page is built from three languages. Think of a house:

• HTML is the walls and rooms.
• CSS is the paint and furniture.
• JavaScript is the electricity — things that react when you use them.

Try it yourself

Make a file called page.html, paste this in, and open it in your browser:

<!doctype html>
<h1 id="title">Hello!</h1>
<button id="btn">Click me</button>
<style>
  h1 { color: teal; font-family: sans-serif; }
</style>
<script>
  document.getElementById('btn').onclick = () => {
    document.getElementById('title').textContent = 'You clicked!';
  };
</script>

• The <h1> and <button> are HTML.
• The color: teal is CSS.
• The click that changes the text is JavaScript.

What to learn next

1. HTML: headings, links, images, forms.
2. CSS: flexbox and grid for layout.
3. JavaScript: variables, functions and events.

Read how a website works to see how these files reach the browser.